1. Field of the Invention
The present invention relates to a plasma reactor. More particularly, the invention relates to a plasma reactor which can reduce the electric power required for generating plasma and can efficiently react components contained in the gas passing through a gas passage.
2. Description of Related Art
In order to remove particulate matter contained in exhaust gas from a diesel engine and the like or to oxidize nitrogen monoxide (NO) into nitrogen dioxide (NO2), a plasma reactor equipped with plasma generating electrodes such as parallel plate-type electrodes, coaxial cylinder-type electrodes, or packed bed-type electrodes is used (see Patent Documents 1 to 3). When using such a plasma reactor, each plasma generating electrode installed in the plasma reactor is connected to one power supply, such as a pulse power supply.
The plasma generating electrodes used in such a plasma reactor have a ceramic dielectric installed between opposing electrodes (conductors). Plasma can be generated by applying an alternating or periodic pulse voltage between the opposing electrodes to produce a silent discharge. Patent Document 2, for example, discloses a plasma reactor having one reaction board (electrode) or two or more segmented reaction boards. Specifically, the patent specification shows a drawing in which a plurality of reaction boards (electrodes) are arranged on the surface of one ceramic dielectric. Patent Document 3 discloses a multi stage reactor having two or more reaction vessels installed in series, in which the reaction vessels on the downstream side are designed to be less energized than the reaction vessels on the upstream side.
(Patent Document 1) Japanese Patent Application Laid-open No. 2001-193441
(Patent Document 2) U.S. Pat. No. 6,482,368
(Patent Document 3) Japanese Patent No. 3089213